This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by NEWTON, J. E. Articles by BETTS, J. E. Search for Related Content PubMed Articles by NEWTON, J. E. Articles by BETTS, J. E.

FACTORS AFFECTING LITTER-SIZE IN THE SCOTCH HALF-BRED EWE

Summary.: Seventy-eight ewes were injected with pregnant mare serum (PMS) during the normal breeding season. Injections of 500, 750, 1000, 1250 or 1500 i.u. of PMS were given on the 12th or 13th day of the oestrous cycle. The number of lambs born per ewe was significantly increased with increasing levels of PMS.

Progesterone injections were given to sixty-three ewes to synchronize oestrus within the flock during the normal breeding season. Injections of 500, 750, 1000, 1250 or 1500 i.u. of PMS were given 1 day after the last progesterone injection. The fertility of mating at the first synchronized oestrus was high. There was a marked increase in the number of lambs born per ewe using 1500 i.u. of PMS.